In our increasingly mobile society, there has been an ever increasing demand for mobile communications to allow a person to roam freely while making and receiving telephone calls from virtually any location. A wide range of wireless systems are in use today and more are now scheduled for near term future deployment, including cellular telephone systems (both analog and digital) and lower power portable handset type systems now commonly referred to as personal communications service (PCS) systems.
Public cellular telephone systems and the emerging low-power, digital cellular PCS systems provide a high degree of mobile communications, as subscribers roam over large geographic areas. However, such systems are expensive to deploy, and as a result, air time charges for use of such systems are high. A number of applications have been recognized where wireless communications are-desirable, but implementation of a full public cellular telephone system is unnecessary. This specification refers to these more limited systems as ‘localized’ wireless or cordless telephone type communications systems.
For example, U.S. Pat. No. 4,980,907 to Raith et al. discloses a wireless communication system with roaming capabilities. Each portable radio terminal can operate at a subscriber's residence as part of residential equipment, or in a commercial subscriber's business area as an extension to a PABX. When away from the normal residential or business location, however, the portable radio terminal can operate through public transceivers referred to as telepoint terminals. Each residential installation, PABX and telephone terminal connects through a telephone line or trunk to an exchange of a public switched telecommunication network (PSTN).
U.S. Pat. No. 4,875,231 to Hara et al. discloses a radio telephone system, which includes a base station connected to a telephone exchange and a plurality of mobile stations. The mobile stations communicate with the base station through a control channel and a number of communication channels.
Each of U.S. Pat. Nos. 4,965,849 and 5,014,295 to Kunihiro discloses a cordless telephone system, wherein the master station connects to two outgoing telephone lines. The master station includes a number of base transceiver units for simultaneously communicating with a number of portable wireless handsets.
U.S. Pat. Nos. 4,878,238 and 5,020,094 to Rash et al. describe a cordless telephone network which allows each hand-held cordless telephone unit to be used with any of a number of strategically located base units, for example located at truck stops, rest areas along interstate highways, convention centers and the like. A base unit connects via a telephone line to a conventional commercial telephone network. The base unit includes an FM transmitter, FM receiver, CPU and a telephone line interface circuit. The Rash et al. Patents mention that it would be possible to have multiple base units at one location, each one being attached to a different land line and each one operating on a cordless telephone channel.
As shown by the above description, the cordless telephone systems utilized in the prior art have all relied on an existing public telephone network to transport communications outside of the cordless telephone systems themselves. In such a situation, for example, a long distance call typically would go through a local exchange carrier to the point of presence of an interexchange carrier for routing to the area of the called party. Although fees and billing arrangements vary widely, each carrier imposes some form of charge for its handling of a portion of such a call. The long distance and international charges by the interexchange carriers, in particular, can be quite high.
Concurrent with developments in wireless communications, outlined above, attention recently has been directed to implementing a variety of communication services, including voice telephone service, over the worldwide packet switched data network now commonly known as the Internet. The Internet had its genesis in U.S. Government programs funded by the Advanced Research Projects Agency (ARPA). That research made possible national internetworked data communication systems. This work resulted in the development of network standards as well as a set of conventions, known as protocols, for interconnecting data networks and routing information across the networks. These protocols are commonly referred to as TCP/IP. The TCP/IP protocols were originally developed for use only through ARPANET but have subsequently become widely used in the industry. TCP/IP is flexible and robust. TCP takes care of the integrity, and IP moves the data.
Internet provides two broad types of services: connectionless packet delivery service and reliable stream transport service. The Internet basically comprises several large computer networks joined together over high-speed data links ranging from ISDN to T1, T3, FDDI, SONET, SMDS, ATM, OT1, etc. The most prominent of these national nets are MILNET (Military Network), NSFNET (National Science Foundation NETwork), and CREN (Corporation for Research and Educational Networking). In 1995, the Government Accounting Office (GAO) reported that the Internet linked 59,000 networks, 2.2 million computers and 15 million users in 92 countries. However, since then it is estimated that the number of Internet users continues to double approximately annually.
In simplified fashion the Internet may be viewed as a series of packet data switches or ‘routers’ connected together with computers connected to the routers. The Information Providers (IPs) constitute the end systems which collect and market the information through their own servers. Access providers are companies such as UUNET, PSI, MCI and SPRINT which transport the information. Such companies market the usage of their networks to the actual end users.
FIG. 5 shows a simplified diagram of the Internet and various types of systems typically connected thereto. Generally speaking the Internet consists of Autonomous Systems (AS) type packet data networks which may be owned and operated by Internet Service Providers (ISPs) such as PSI, UUNET, MCI, SPRINT, etc. Three such AS/ISPs appear in FIG. 5 at 310, 312 and 314. The Autonomous Systems (ASs) are linked by Inter-AS Connections 311, 313 and 315. Information Providers (IPs) 316 and 318, such as America Online (AOL) and Compuserve, connect to the Internet via high speed lines 320 and 322, such as T1/T3 and the like. Information Providers generally do not have their own Internet based Autonomous Systems but have or use Dial-Up Networks such as SprintNet (X.25), DATAPAC and TYMNET.
By way of current illustration, MCI is both an ISP and an IP, SPRINT is an ISP, and the MicroSoft Network (MSN) is an IP using UUNET as its ISP. Other information providers, such as universities, are indicated in exemplary fashion at 324 and are connected to the AS/ISPs via the same type connections here illustrated as T1 lines 326. Corporate Local Area Networks (LANs), such as those illustrated in 328 and 330, are connected through routers 332 and 334 and high speed data links such as T1 lines 336 and 338. Laptop computers 340 and 342 are representative of computers connected to the Internet via the public switched telephone network (PSTN) and are shown connected to the AS/ISPs via dial up links 344 and 346.
Recently, several companies have developed software for use on personal computers to permit two-way transfer of real-time voice information via an Internet data link between two personal computers, for example between PCs 340 and 342. In one of the directions, the sending computer converts voice signals from analog to digital format. The software facilitates data compression down to a rate compatible with modem communication via a POTS telephone line, in some cases as low as 2.4 kbits/s. The software also facilitates encapsulation of the digitized and compressed voice data into the TCP/IP protocol, with appropriate addressing to permit communication via the Internet. At the receiving end, the computer and software reverse the process to recover the analog voice information for presentation to the other party. These programs permit telephone-like communication between Internet users.
PCs having voice communication capabilities can conduct two-way, real-time audio communications with each other, in a manner directly analogous to a two-way telephone conversation. However, the actual signals exchanged between two such terminal devices go through the public packet data network. Typically, such communications at least bypass long distance interexchange carriers.
Internet based telephone programs have relied on servers (not separately shown) coupled to the Internet to establish voice communication links through the networks. Each person active on the network, who is willing to accept a voice call, must register with a server. A calling party can call only those persons registered on the voice communication server.
The development of the Internet, particularly voice telephone communication over the Internet, has been separate from efforts to develop and deploy localized wireless or cordless telephone type communications systems. For example, the PCs and server systems on the market today apparently have not permitted calling through the Internet to wireless telephone subscribers, particularly when roaming. As a result, a need still exists to find an effective cheaper alternative to the transport of calls to and from wireless systems via telephone carrier networks. More specifically, a need exists to provide a localized wireless or cordless telephone type communications system which can at least selectively provide voice traffic transport over a public packet switched data network, such as the Internet. A need further exists for systems and call processing methodologies to facilitate easy calling and efficient routing of calls to and from such a system, via the public packet data network.